GB492094A - Improvements in or relating to excitation control of electric generators - Google Patents

Abstract

492,094. Transmitting mechanical power. BURGE, H. O., MATHEWS, D. C. H., and CROMPTON PARKINSON, Ltd. Jan. 7, 1937, No. 535. Drawings to Specification. [Class 38 (iv)] Boosting.-The power in an electric generator, in a Diesel-electric plant for example, is maintained constant by including a booster in its excitation circuit to vary the generator excitation in accordance with the generator output current, and the field of the booster is designed to obtain saturation at predetermined upper and lower limits of that current, the external characteristic of the generator being, therefore, of substantially hyperbolic form over a desired range of current variation. The booster has a self-excited field winding and further excitation which depends on opposing influences of a constant value and of a value varying with generator current, so that the booster potential passes from a maximum in one direction to a maximum in the other, these maximum being limited by the saturation of the field. The following arrangements of the booster are described : (1) with self-excitation and other field windings energized respectively by a constant voltage source and the generator output; (2) with self-excitation and a winding fed from a reversing potentiometer operated by a solenoid in the generator output circuit ; (3) with self-excitation and other field windings energized respectively from a constant voltage source and by the difference between the voltage of that source and of the generator (the generator voltage varying inversely with its output current) ; and (4) with self-excitation and a winding fed differentially from a constant voltage source and the voltage of an axledriven generator with constant excitation.